The key milestone was to successfully re-engine Antares with a new type of first stage engine that completely eliminates use of the original AJ26 engines that were refurbished 40 year leftovers – the NK-33 from Russia’s abandoned manned moon landing program.

After the launch failure, Orbital managers decided to ditch the trouble plagued AJ-26 and “re-engineered” the vehicle with the new RD-181 Russian-built engines that were derived from the RD-191.

Soviet era NK-33 engines refurbished as the AJ26 exactly like pictured here probably caused Antares’ rocket failure on Oct. 28, 2014. Orbital Sciences technicians at work on two AJ26 first stage engines at the base of an Antares rocket during exclusive visit by Ken Kremer/Universe Today at NASA Wallaps. These engines powered the successful Antares liftoff on Jan. 9, 2014 at NASA Wallops, Virginia bound for the ISS. Credit: Ken Kremer – kenkremer.com

NASA has recently supplemented the CRS contract with three additional Cygnus resupply deliveries in 2017 and 2018.

However, the Cygnus missions were put on hold when the third operational Antares/Cygnus flight was destroyed in a raging inferno about 15 seconds after liftoff on the Orb-3 mission from launch pad 0A at NASA’s Wallops Flight Facility on Virginia’s eastern shore.

Until Antares flights can safely resume, Orbital ATK has contracted with rocket maker United Launch Alliance (ULA) to launch a Cygnus cargo freighter atop an Atlas V rocket for the first time, in early December – as I reported here.

The Antares rocket is being upgraded with the new RD-181 main engines powering the modified first stage core structure that replace the troublesome AJ26 engines whose failure caused the Antares Orb-3 launch explosion on Oct. 28, 2014.

“We are making excellent progress in resuming our cargo delivery service to the International Space Station for NASA under the Commercial Resupply Services (CRS) contract,” said company officials.

Orbital ATK engineering teams have been working diligently on “integrating and testing the new RD-181 main engines.”

After engineers finished acceptance testing and certification of the RD-181, the first dual engine set was shipped to Orbital’s Wallops Island integration facility. They arrived in mid-July. A second set is due to arrive in the fall.

“The RD-181 engine provides extra thrust and higher specific impulse, significantly increasing the payload capacity of the Antares rocket. This state-of-the-art propulsion system is a direct adaptation of the RD-191 engine, which completed an extensive qualification and certification program in 2013, accumulating more than 37,000 seconds of total run time,” said Scott Lehr, President of Orbital ATK’s Flight Systems Group, in a statement.

Engineers and technicians have now “integrated the two RD-181 engines with a newly designed and built thrust frame adapter and modified first stage airframe.”

Then they will add new propellant feed lines and first stage avionics systems.

Then comes the moment of truth. A “hot fire” test on the launch pad will be conducted by either the end of 2015 or early 2016 “to verify the vehicle’s operational performance and compatibility of the MARS launch complex.”

“Significant progress has been made in the manufacture and test of the modified hardware components, avionics and software needed to support the new engines,” said Mike Pinkston, Vice President and General Manager of Orbital ATK’s Antares Program.

Simultaneously, teams have been working hard to repair the Wallops launch pad which was damaged when the doomed Antares plummeted back to Earth and exploded in a hellish inferno witnessed by thousands of spectators and media including myself.

Repairs are expected to be completed by early 2016 to support a launch tentatively planned for as soon as March 2016.

Out with the old and in with the new! Am glad Orbital ATK has found a replacement rocket engine but still wish it was American made! What’s up with that? Besides SpaceX, Rocketdyne and Aerojet, who else is stepping into the market? When will an all new heavy lift American made rocket engine fly?

In particular, I recommend that you look at the Raptor engine being developed by SpaceX. It is the first liquid-fueled engine since the F-1 on the Saturn V to provide true heavy-lift levels of thrust. (It is supposed to produce about 1 million pounds of thrust using Methane and LOX – basically, about three times the thrust of a SSME.)